17 



The two adult males from Stat. 85 are 103 resp. 102 mm. long, twice as large as 

 the single female, long 50 mm., from the Travancore coast, on which this species was founded. 

 It is a retnarkable fact that some species of this genus resemble one another so closely, even 

 in minute details. This is also the case with the present species, which bears such a close 

 resemblance to Stereom. phosphoriis, except of course in a few specific characters, that it suffices 

 to refer to Plate VIII, Fig. 2 of the "Illustrations of the Zoology of the Investigator" and to 

 the measurements, in order to give a good idea also of Stereom. andamanensis. The general 

 shape of carapace, abdomen and appendages is indeed quite the same. In one male from 

 Stat. 85 the anterior division of the left lateral border of the carapace is armed with 6 spines, 

 including the spine at the antero-lateral angle, the middle division with 3, the posterior with 

 8 and the sublateral ridge that runs parallel with the latter division, also with 8 spines; 

 this armature may be indicated by the formula 3 . The formula for the right side is 3, both 



8.8 8,7 



sublateral ridges on the branchial regions carrying eight spines. The spines are disposed exactly 



like in the quoted figure of Stereom. phospJwriis: of the posterior division the fïrst 4 or 5 are 



placed much closer together than the following and the last spine of the sublateral ridge is 



situated likewise a little more laterally than the preceding. The formulae for the other male 



of this Station are * for the left, and ■* for the right side. As rerards the other spines that 



8.7 7.7 ° ö r 



occur on the carapace, both specimens agree with Stereom. phosphortis. A small acute tubercle 

 is situated on the frontal border of the eye-stalk somewhat nearer to the outer than to the 

 inner angle of the orbital notch. The two rostral spines are coalesced until the middle in one 

 male, less far in the other. The spinule at the inner angle of the orbital notch is directed 

 straight forward and obliquely upward. The two adult specimens from Stat. 314 agree with 

 those just described. In the male, long 95 mm., the armature of the lateral margins is indicated 

 for the left side by the formula * , for the rig-ht by the formula s- in the female, which is 



J 8.6 ' 6 "■' 



86.5 mm. long, the formula is for each side s, while the sublateral ridge presents 7 spines 

 also on each side. As regards the other spines on the upper surface of the carapace, these 

 specimens agree with those from Stat. 85. The formulae of the lateral borders are in the young 

 male from Stat. 137, which is 46 mm. long, on the left side a , on the right also ^3. The 

 carapace of the young female from Stat. 48, finally, is mutilated on the left side, on the right 

 the formula is »: this specimen measures 44 mm. These formulae indicate that the number 

 of spines is slightly variable and that, as in Alcock's young female, the sublateral ridge on the 

 branchial region presented also only 5 spines ; this number seems to occur constantly in the 

 young female. 



Beneath the hairy tomentum with which the carapace is covered, it appears somewhat 

 granular on the branchial regions between the sublateral ridge and the oblique groove that 

 defines the cardiac region. 



In the young female from Stat. 48 one observes, exactly as in the equally long type 

 from the Travancore coast, 3 or 4 spinules between the anterior pair of spines on the cardiac 

 region and the spine at lhe bifurcation of the cervical groove : these spines do no more occur 

 in the adult. Like in the young type, the oblique grooves that border the cardiac region 

 laterally, are also armed posteriorly with spines. On each side of the hindmost pair of spines 



SIBOGA-EXrEDlTIE XXXIX a-. 



